The present application relates to a secondary battery including an anode having an anode active material layer.
In recent years, portable electronic devices such as combination cameras (videotape recorder), mobile phones, and notebook personal computers have been widely used, and it is strongly demanded to reduce their size and weight and to achieve their long life. Accordingly, as a power source of the portable electronic devices, a battery, in particular a light-weight secondary batter capable of providing a high energy density has been developed.
Specially, a secondary battery using insertion and extraction of lithium for charge and discharge reaction (so-called lithium ion secondary battery) is extremely prospective, since such a secondary battery is able to provide a higher energy density compared to a lead battery and a nickel cadmium battery. The lithium ion secondary battery has a cathode, an anode, and an electrolytic solution. The cathode has a cathode active material layer on a cathode current collector. The anode has an anode active material layer on an anode current collector.
For a composition of the electrolytic solution used for the lithium secondary batteries, to improve the battery characteristics such as cycle characteristics, technologies using various organic acids have been proposed. As the organic acid, formic acid, acetic acid, oxalic acid, malonic acid, maleic acid, fumaric acid, benzoic acid and the like have been used (for example, as described in Japanese Unexamined Patent Application Publication Nos. 2000-012079 and 2006-351242).
For the foregoing organic acids, a technique using the organic acid for a cathode, an anode and the like in addition to the technique using the organic acid for the electrolytic solution. As the organic acid, oxalic acid, succinic acid, malonic acid, adipic acid, sebacic acid, phosphoric acid and the like have been used, and the metal salts thereof have been also used (for example, as described in Japanese Unexamined Patent Application Publication Nos. 09-190819, 09-190820, 2004-335379, 2005-011594, and 2006-134584).